Hajime falls into the Orcus Labyrinth and fights to survive and eventually return home. This is not that story. This is the spin-off slapstick series of Hajime's adventure with the various heroines and all the ridiculous hi-jinks happen along the way. Essentially take the bonus chapters and apply that comedy to the main series, and make it even funnier.

Why:

It would be a great launch title. Arifureta is already familiar to a lot of people now and I think people that enjoy the comedy (particularly me) would love to get a lot more of the silly stuff from the manga spin-off. J-NC already has the main series and the prequel. With manga publication coming, might as well capture the last piece of unlicensed Arifureta before the anime airs next year. (2019)

It's got comedy, romance, and even a bit of (literal) flaming heart action.

Oh that's right. Now that JNC said they're doing manga starting this fall, people can suggest some. Myskaros may start another list for manga, but I'm not going to bother adding it to mine. I'll keep it to just light novels.

This one does seem like an obvious choice along with any of the manga adaptations of their light novels. Hopefully JNC will eventually tackle some that other publishers don't want to print due to their length. I'm looking at you 7Seeds.